<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <ul id="parent-list">
        <li id="post-1">Item 1</li>
        <li id="post-2">Item 2</li>
        <li id="post-3">Item 3</li>
        <li id="post-4">Item 4</li>
        <li id="post-5">Item 5</li>
        <li id="post-6">Item 6</li>
    </ul>
    <button id="addLi">添加一个li</button>
</body>
<script src="js/jquery.min.js"></script>
<script>
$('#parent-list').on('click', 'li', function(){
    alert($(this).text())
})
$('#addLi').on('click', function(){
    $('#parent-list').append('<li>Item new</li>')
})
</script>
</html>